This invention relates to an apparatus for reducing jet engine exhaust noise, and more particularly to using oscillating jets to reduce jet engine exhaust noise.
The reduction of engine noise generated by jet aircraft engines is becoming an important aspect of jet engine design. This is true in both commercial and military applications, where the reduction of noise has obvious benefits. Additionally, the reduction of noise is beneficial to increasing the operational life of a jet engine and engine components because noise can contribute to the wear and sonic fatigue of engine components.
Various methods have been developed to decrease jet aircraft engine noise. However, these methods are not without their disadvantages. For example, chevrons and other geometric modifications have been employed in engine exhaust systems to enhance the mixing of the jet engine exhaust flow to reduce noise. However, these methods typically result in engine performance penalties, including thrust reduction and adverse effects on specific fuel consumption. These penalties are compounded by the fact that these mechanical devices require additional components and moving parts which add cost, weight and complexity to the engine. Further, many of these systems permanently exist in the engine exhaust system and cannot be turned off, or otherwise deactivated, when they are not needed.
Thus, fluidic devices that can be used in jet engine exhaust systems, which require no additional moving parts or complex systems, and can be turned off when noise suppression is not needed, are desirable.